Partial support is requested for the symposium "The Biological Basis of Human Longevity," which will be held at the 41st Annual Meeting of The Gerontological Society of America in San Francisco, California. The Gerontological Society of America is the largest scientific society in gerontology in the United States and is therefore the largest organization to host symposia concerned with human aging and longevity. This symposium will be part of the annual program of the Biological Sciences Section of this Society. The proposed symposium for this meeting will summarize our state of knowledge, recent advances and new concepts and ideas concerning the genetic and biochemical basis determining longevity and the aging rate of humans. Knowledge of this topic is essential four our understanding of the biological basis of human health and longevity and to also provide new insights into the mechanisms of aging. A multidisciplinary approach is necessary to properly present this topic, which ranges from the fields of evolution and comparative biology to those of molecular genetics and recombinant DNA. The symposium is divided into six sessions. Session one focuses on recent advances in the comparative biology of mammalian species to highlight possible unique morphological, genetic and biochemical characteristics that correlate with lifespan. The second session focuses on recent advances on the molecular- genetic basis of speciation. Emphasis is placed on the possible role regulatory genes may have in governing the major aspects of primate evolution. Since lifespan is a species characteristic, knowledge of mechanisms in speciation could lead to new insights into the genetic basis governing aging rate and, accordingly, this possibility will also be explored. Session three reviews the key hypotheses of both senescence and longevity, placing an emphasis on the fundamental differences of these two models. Sessions four and five focus on genetic instability of regulatory genes as a possible important factor in aging. Session six concerns the possible repair and defense mechanisms against active oxygen species that may have evolved to increase the stability of the differentiated state of cells during the evolution of increases longevity. The symposium is expected to be of interest to the other disciplines represented by our Society, and a series of three general lectures will be given to help facilitate communication to non-biological members. A special effort will be made to advertise the symposium on a nationwide level and the proceedings will be published.